Above-ground petroleum storage tanks, chemical storage tanks and similar facilities typically utilize a secondary containment system for capturing hazardous liquid that leaks or spills from the tank. Secondary containment is also used for retention ponds, lakes and similar facilities to prevent polluting substances such as drill water, acids, gasses and unsafe chemicals from entering the water table. Conventional secondary containment systems employ an impermeable or impervious liner that extends across a basin or retention area. The liner, which is designed to prevent petroleum, chemicals or other hazardous materials from seeping into the ground, typically comprises a plurality of juxtaposed geotextile fabric panels. These panels are cut as required, arranged across the containment area and then sprayed with a polyurea coating that renders the panels impermeable to the passage of liquids discharged from the tank or otherwise held in the retention facility.
Assembling and installing secondary containment panels onsite presents a number of problems. Most significantly, when the polyurea is sprayed onto the geotextile fabric in the field, a significant amount of the impermeable coating is apt to be dissipated, lost and wasted due to wind and/or rain. Outdoor weather conditions tend to complicate the application process considerably. In order to provide the completed panels with a stippled, slip-resistant surface, the polyurea coating must be sprayed onto the geotextile fabric from a distance of about several feet or more. This separation causes at least some of the sprayed coating to dissipate and miss the fabric entirely, particularly under windy conditions. Indeed, in a typical secondary containment system, as much as 25% of the coating material can be wasted when it is applied outdoors and onsite. The evenness or uniformity of coating coverage on the surface of the fabric also varies tremendously.
An additional disadvantage accompanying conventional coating application procedures is that large amounts of polyurea coating and affiliated applicator equipment must be transported to and from the secondary containment site. The coating itself is typically transported to the site in 55 gallon drums. After the drums are emptied and the coating applied to the geotextile fabric, the drums must be removed for disposal. In addition, bulky applicator equipment including pumps, hoses, etc. must be transported to and from the secondary containment site. All of this adds to the complexity and expense of installing the secondary containment system.